1. Field of the Invention
The present invention relates to the delivery of a shunt and other devices into the myocardium of a patient, and more particularly, to the delivery of a generally L-shaped shunt to provide a bypass through the myocardium from the left ventricle into a coronary artery.
2. Description of the Related Art
Coronary arteries as well as other vessels frequently become clogged with plaque that at the very least impairs the efficiency of the heart""s pumping action and can lead to heart attack and death. One conventional treatment for clogged coronary or other arteries is a bypass operation wherein one or more venous segments are inserted between the aorta and the coronary artery. The inserted venous segments or transplants act as a bypass of the clogged portion of the coronary artery and thus provide for a free or unobstructed flow of blood to the heart.
Such coronary artery bypass surgery, however, is expensive, time-consuming and traumatic to the patient. Hospital stays subsequent to the surgery and convalescence are prolonged.
A new coronary artery bypass technique is disclosed in U.S. Pat. No. 5,429,144. That technique utilizes a stent made of a biocompatible material and comprises steps of moving the stent in a collapsed configuration through a blood vessel of a patient""s vascular system to the patient""s heart, inserting the stent in the patient""s myocardium, and upon disposition of the stent in the myocardium, expanding the stent from the collapsed configuration to a substantially tubular expanded configuration so that a blood flow path is formed at least partially through the myocardium.
U.S. Pat. No. 5,755,682 to Knudson discloses an L-shaped shunt (see FIG. 1A of Knudson) having one end in the lumen of an artery facing downstream from an obstruction and the other end in fluid communication with blood within the heart chamber. One problem with using this L-shaped shunt is how to get the shunt into the myocardium without undue trauma to the patient.
The problem of delivering an L-shaped shunt or conduit is solved herein by providing an improved catheter delivery system. A shunt preferably made of semirigid material is inserted into the lumen of a delivery catheter. The delivery catheter is advanced within the patient until its distal end is located adjacent to the desired insertion site, which is preferably the junction between a coronary artery and passageway formed in the myocardium between the left ventricle and coronary artery. A proximal section of the shunt is first advanced out of the delivery catheter into the myocardial passageway. A distal section of the shunt is advanced into the coronary artery, preferably by advancing the distal section of the shunt into the myocardial passageway and then pulling the distal section back into the coronary artery, or by pushing the distal section of the shunt in a folded configuration out of the delivery catheter into the coronary artery. In one embodiment, the shunt is made of a collapsible material for insertion into the delivery catheter, the shunt expanding upon removal from the delivery catheter.
In one aspect of the present invention, a method of delivering a conduit into a portion of the body having a first passageway and a second passageway joined generally at an angle is provided. A delivery catheter is advanced into the patient, the delivery catheter having a proximal end and a distal end and a lumen extending therethrough. The delivery catheter once advanced has a proximal end that extends outside of the patient and a distal end located substantially adjacent the location where the first passageway and the second passageway are joined. A conduit is inserted into the lumen of the delivery catheter, the conduit having a proximal section and a distal section. The proximal section of the conduit is advanced out of the lumen at the distal end of the delivery catheter into the first passageway. The distal section of the conduit is advanced into the second passageway.
In another aspect of the present invention, a method for creating a bypass between a chamber of the heart and a blood vessel adjacent to that chamber is provided. A passageway is formed in a heart wall that extends between the chamber of the heart and the blood vessel. The passageway has a proximal end opening into the chamber of the heart and a distal end opening into the blood vessel. A conduit is advanced having a proximal end and a distal end through the distal end of the passageway toward its proximal end. The proximal end of the conduit once advanced extends past the heart wall into the chamber of the heart, and the distal end of the conduit once advanced is located in the heart wall. The distal end of the conduit is advanced out of the distal end of the passageway and into the blood vessel downstream of the passageway.
In another aspect of the present invention, a method for creating a bypass between a chamber of the heart and a blood vessel adjacent to that chamber is provided. A passageway is formed in the heart wall that extends between the chamber of the heart and the blood vessel. The passageway has a proximal end opening into the chamber of the heart and a distal end opening into the blood vessel. A conduit having a proximal end and a distal end is folded to define a proximal section and a distal section between the fold. The folded conduit is inserted into a delivery catheter having a proximal end and a distal end and a lumen extending therethrough. The conduit is inserted such that the proximal end of the conduit is nearer to the distal end of the delivery catheter than the distal end of the conduit is to the distal end of the delivery catheter. Both the proximal end and the distal end of the conduit face toward the distal end of the delivery catheter. The delivery catheter is advanced into a patient into the blood vessel until its distal end is adjacent to the distal end of the passageway in the heart wall. The proximal section of the conduit is advanced out of the lumen at the distal end of the delivery catheter into the passageway. The distal section of the conduit is advanced out of the lumen at the distal end into the blood vessel.